Such rollers are generally used to keep the belt or chain tension always within a determined range or to make a local alteration to the path followed by this belt or chain. In the case of winding rollers, the pulley is mounted for rotation on a spindle via a rolling bearing, the roller then being fixed directly or indirectly to the engine block or to a part of the tensioning roller device, for example an articulated arm or an eccentric.
In many types of belt or chain rollers of the prior art, the pulley is overmolded onto the outer ring of the rolling bearing which is itself mounted directly on a fixing spindle attached to the engine block. Thus, the diameter of the bore in the inner ring has to be adapted to suit the radial dimension of the spindle used by the motor vehicle manufacturer. That runs counter to the practice of standardizing the rolling bearings used for such applications.
Document DE-A1-100 35 488 describes a mounting device for a belt pulley comprising a sleeve tube provided with a flange that forms a spacer piece for the inner ring of the rolling bearing, and with a retaining tube collaborating with the sleeve tube to press against the inner ring axially on the opposite side to the flange.
This solution has the disadvantage of entailing the use of two distinct elements in addition to the assembly formed of the rolling bearing and of the pulley, something which is disadvantageous for transporting, handling and fitting these elements.
Document FR-B1-2 758 375 describes a tensioning roller comprising a pivoting body, a rolling bearing mounted on the said body, and a bushing made of metal to accept the fixing spindle intended to be attached to the engine block. The pivoting body is obtained by overmolding a synthetic material in the bore of the rolling bearing and over the exterior surface of the bushing.
Again, document DE-U1-298 05 581 discloses a tensioning roller comprising a rolling bearing, a pulley overmolded on the outer ring of the rolling bearing, and a filler piece overmolded in the bore of the inner ring of the rolling bearing and on a fixing spindle.
The tensioning rollers described in these two documents have the major disadvantage that they cannot be easily adapted to suit the size of the spindle or of the fixing screw designed to be mounted on the engine block.